Nuclear Power

En 1986, 16.000 personas vivían en la ciudad ucraniana de Chernobyl. En el 26 del mes de abril ocurrió una tragedia, un reactor nuclear cercana exploted. Este relaise toneladas de materiales radiactivos al medio ambiente. Con el fin de apagar las llamas, helicópteros cayeron 5.000 toneladas de arena y otros materiales al reactor. La explosion causado la muerte de 30 bomberos y trabajadores en el reactor y 161.000 personas tuvieron que abandonar sus hogares.

Hoy en día, 30 años después, el lugar todavía no está seguro, como toneladas de material radiactivo peligroso permanecen en el reactor y se cree que 3 millones de personas todavía están contaminados. Así que nadie puede predecir el número de víctimas finales.

Así que mi pregunta es, ¿es bueno utilizar la energía nuclear o debemos utilizar únicamente energías renovables?

 

Resultado de imagen de nuclar energyResultado de imagen de chernobyl

Oil spill

Oil is very important nowadays. But does it compense with all the damage it produces to the enviroment?

TheExxon Valdez was a big oil tanker. It was transporting oil when an accident took place in Alaska. For avoid an iceberg the captain of the ship took another route and the ship finally struck on a reef. 40 million litres of oil were spill on the sea. It polluted 28,000 km. The clean-up lasted 3 summers and cost  $ 2 billion.

Oil spill is really harmful for the environment: animals die, the ecosystem is destroy, the cleaning is really expensive…  In addition after the catastrophe in the damaged area people won´t  be able to fish again. And tourist won´t be possible.

Even if the area has been cleaned animals that live under the sand, like crabs, will die because they won´t find anything to eat.

Maybe we can find other ways to transport oil because this one is ending with our planet. We are ending with our planet.

Resultado de imagen de oil spill

Resultado de imagen de oil spill

Stellar Processes and Evolution-Solar Mass Stars

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This is the process and the evolution of a Solar Mass Star:

  1. The star’s core is made up of helium and surrounded by a hydrogen shell.
  2. As hydrogen burns faster, it comes to an end and is not sufficient for helium to start burning.
  3. The radiactive pressure goes outwards to resist gravitational collapse. In the outer regions temperature increases and hydrogen fusion can occur.
  4. The core continues to collapse and the outer regions keep increasing their temperature and luminosity. Now everything exerts a pressure.
  5. Pressure makes the outer layers to expand, they cool down and the star becomes redder. After millios of years the hydrogen shell runs out of fuel.
  6. The star turns into a red giant and is seen as a nebula leaving a core behind.
  7. The core has half of the mass of a star and will eventually cool down.
  8. The atoms are packed and the star turns into a white dwarf.

Medium mass stars

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Medium mass stars have a complex evolution. In the first phases they evolve in the same way as low mass stars.

When the helium core is exhausted the stellar collapse occurs and the outer layers reignite. Then, the outer shell of hydrogen burning, the inner shell of helium burning and the core would be shown.

In this moment the Carbon supply is exhausted. Several layers transform into others, for example the helium shell becomes a carbon one. At this point in the life of the star the last fusion (the one that produces less energy) is the one of chromium into iron. During these final stages the star expands becoming a red supergiant.

Finally there is a problem; the star hasn’t got enough energy nor to separate neither to fuse elements. As a result the pressure that supported the star disappears and the star undergoes a gravitational collapse.

After the collapse the star becomes a neutron star because the protons and electrons in the core are compressed into a ball of neutrons. A pulsar is a neutron star that produces electromagnetic emissions.

 In the last moments of a medium mass star’s life it collapses becoming a supernovae. Then it is able to fuse elements like gold and uranium, rapidly ejects them to the outer space together with huge amounts of energy.

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Don´t miss out on the supermoon!

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The moon is a familiar sight in our sky, brightening dark nights and reminding us of space exploration, past and present. But the upcoming supermoon — on Monday, Nov. 14 — will be especially “super” because it’s the closest full moon to Earth since 1948. We won’t see another supermoon like this until 2034.

The moon’s orbit around Earth is slightly elliptical so sometimes it is closer and sometimes it’s farther away. When the moon is full as it makes its closest pass to Earth it is known as a supermoon. At perigee — the point at which the moon is closest to Earth — the moon can be as much as 14 percent closer to Earth than at apogee, when the moon is farthest from our planet. The full moon appears that much larger in diameter and because it is larger shines 30 percent more moonlight onto the Earth.

Watch this video from NASA to find out more facts about supermoon.

Do you dare to take a picture of November, 14th supermoon?

A pale blue dot

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Transcription

Look again at that dot. That’s here. That’s home. That’s us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every “superstar,” every “supreme leader,” every saint and sinner in the history of our species lived there–on a mote of dust suspended in a sunbeam.

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Black Holes

Don’t let the name fool you: a black hole is anything but empty space. Rather, it is a great amount of matter packed into a very small area – think of a star ten times more massive than the Sun squeezed into a sphere approximately the diameter of New York City. The result is a gravitational field so strong that nothing, not even light, can escape. In recent years, NASA instruments have painted a new picture of these strange objects that are, to many, the most fascinating objects in space.

Black holes were predicted by Einstein’s theory of general relativity, which showed that when a massive star dies, it leaves behind a small, dense remnant core. If the core’s mass is more than about three times the mass of the Sun, the equations showed, the force of gravity overwhelms all other forces and produces a black hole.

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